Signal Path Loss Simulation of Human Arm for Galvanic Coupling Intra-Body Communication Using Circuit and Finite Element Method Models

Galvanic coupling intra-body communication involves the formation of a network between small terminals applied to the surface of the human body and bio-signal sensors embedded within the body. To enable the design of a communication device, it is important to fully understand the signal transmission loss characteristics of the human body, while developing a method that optimizes the transmission efficiency. This study analyzed the signal path loss during galvanic-coupling intra-body communication of a human arm through the application of a four-terminal circuit and a finite-element method (FEM) model, with special attention given to the return path. The effect of the interface circuit of an LC series -- parallel circuit that injected the signal into the human body was also examined. Without the LC series-parallel circuit, the attenuation of the transmitted signal was minimized within a range of 2-5 MHz in the circuit model and 3-7 MHz in the FEM model. The addition of the LC series-parallel circuit improved the attenuation by 1.9-5.8 dB at the resonant frequency (2 MHz).